After decades of 3D modelling, I am constantly amazed at the power of this free-to-hobbyists software. Not perfect, and occasionally irritating, but super powerful.

Posted by: @crab

... I've used OpenSCAD, but that is really a programming environment and very unique (and can be difficult). If you are a programmer, that might be appealing, though. 

Yes, and if you are a programmer knowing JavaScript you do not need to learn a new language if using JSCAD.
A very helpful feature is JSCAD share link ability, see this 70 line embedding on torus as example:
https://jscad.app/#https://gist.githubusercontent.com/Hermann-SW/c47291d47c1c5d14933707fa83da46fb/raw/utility.jscad

The link below is just one of many, many CAD software reviews you can find online that looks at both OnShape and Fusion and others. I'm sure you can find many videos that recommend OnShape and many that recommend Fusion.

CAD Software review

I'd try both and see which one 'fits'. My experience with Fusion is that there are so many great tutorial and courses available for it.. but you need to spend significant time learning which ever one you choose. Those hours will pay off enormously as you build your expertise and your design expertise will improve as your design time decreases.

Since recently it has animation sliders like OpenSCAD.
I use it for 3Dprinting with my Prusa MINI+, but as 3D graphic backend as well:
Select a graph and then press "stereographic projection", that makes JSCAD open with stereographic projection of the planar embedding:
https://hermann-sw.github.io/planar_graph_playground/

Posted by: @electrofrank

I am intending to buy a Prusa i3 MK3S+.    I want to start my journey by getting to grips with 3D CAD sofware, to design the things I want to print.

I cannot find anywhere on the Prusa site that gives information on design software (why is this missing, or hard to find ?).

I had a go at Tinkercad, but found it impossible.   I want to design simple engineering parts for various purposes, including gears.

Please can someone offer advice on where to start, what software is easy to begin learning and designing on ?

 

 

Well its an old post but still relevant today so I will chime in for all the current Newbs to 3D printing and design.  3D Printer Mfrs and Retailers don't mention CAD software because (for most people) its very hard to learn and very expensive.  If you knew just how much so you probably wouldn't buy a printer.  I use TinkerCAD for most everything and it works for most everything but is horrible if you need to go back and make changes to a dimension and for large projects with many parts and for designs with curves.  You are just manipulating premade building blocks in TinkerCAD.  I used Fusion360 Free Version for a couple years and made up some pretty nice functioning RC boats, including hulls, gear boxes, etc. and custom furniture that I could not have done in TinkerCAD.  Then after a few updates or so all my files were gone, the app would no longer open on my PC.  Well over a year's worth of work gone (the unfinished projects not yet converted to STL and downloaded to my PC).  Fusion360 wants to be a power player for business and does not want to bother with individual home users any more.  Now its $680 a year for one person - too rich for my home RC hobby.  I tried FreeCAD and al the other Free CADs around the net and didn't have much luck learning them without a class and an instructor.  Fusion360 was the best IMO but like I said, at $680 a year, way too expensive for anyone not making good money off their designs.  Maybe some company will step in to fill the void left in the hobbyist market by Fusion360 and provide a similar product for home use at around $99 or so a year.  Meanwhile, use TinkerCAD while it lasts and start learning something else like FreeCAD with no expectations of making anything complex, like your imagination envisions, for at least a few months, maybe even a year or more.  Yup, that's why they don't mention design software, they only mention downloading what others have already designed.